Voltage-gated sodium channel alpha subunits Nav1.1–Nav1.7 (Nav1.1–Nav1.7)

Voltage-gated sodium channels (Nav1.1–Nav1.7) are a family of transmembrane proteins that play a fundamental role in the generation and propagation of action potentials in excitable tissues. These channels are composed of a large, pore-forming alpha subunit (encoded by genes SCN1A-SCN5A, SCN8A, and SCN9A) and auxiliary beta subunits that regulate channel trafficking and kinetics. Nav1.1, Nav1.2, Nav1.3, and Nav1.6 are predominantly expressed in the central nervous system and are critical for neuronal excitability; mutations in these isoforms are frequently associated with various epilepsy syndromes. Nav1.4 and Nav1.5 are the primary isoforms in skeletal and cardiac muscle, respectively, where they mediate muscle contraction and maintain cardiac rhythm. Nav1.7 is highly expressed in peripheral sensory neurons and acts as a threshold-setting gatekeeper for pain signaling, with its dysfunction linked to severe pain disorders or congenital insensitivity to pain. Pharmacological targeting of these channels involves a wide range of drugs, including local anesthetics, antiarrhythmics, and anticonvulsants, which typically act by blocking the aqueous pore or stabilizing the inactivated state of the channel. Current drug discovery efforts focus on developing subtype-selective inhibitors, particularly for Nav1.7, to provide effective analgesia without the dose-limiting side effects associated with non-selective blockade of cardiac or central nervous system isoforms.

Other names

Sodium channel protein type 1 subunit alphaSodium channel protein type 2 subunit alphaSodium channel protein type 3 subunit alphaSodium channel protein type 4 subunit alphaSodium channel protein type 5 subunit alphaSodium channel protein type 8 subunit alphaSodium channel protein type 9 subunit alphaSCN1ASCN2ASCN3ASCN4ASCN5ASCN8ASCN9ANav1.1Nav1.2Nav1.3Nav1.4Nav1.5Nav1.6Nav1.7Voltage-gated sodium channel alpha subunits

Voltage-gated sodium channels (Nav1.1–Nav1.7) are primarily targeted by drugs that act as pore blockers or state-dependent inhibitors. Most clinical agents, such as local anesthetics and anticonvulsants, bind to a conserved receptor site within the internal pore of the alpha subunit, physically obstructing the flow of sodium ions. Many of these drugs exhibit state-dependent binding, showing a higher affinity for the inactivated state of the channel, which allows them to selectively inhibit high-frequency firing in pathological conditions like epilepsy or arrhythmia while sparing normal activity. Newer investigational compounds target the voltage-sensing domains (VSDs) to achieve subtype selectivity, particularly for Nav1.7, by modulating the channel's gating transitions.